Changes in Catecholamine Levels in Short Day-Induced Cotyledons of Pharbitis nil

We investigated the effects of catecholamine on flower-induction in P. nil (cv. Violet). GCSIM analysis identified dopamine for the first time in P. nil seedlings. Dopamine levels in the cotyledons did not show a significant change during the inducing dark treatment. The dopamine content of cotyledons exposed to various durations of darkness were 0.1-0.2 nmol/ g fresh weight. The same content was found when cotyledons were exposed to continuous light.

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Magnesium localization in shoot apices during flower induction in Pharbitis nil

Canadian Journal of Botany ◽

10.1139/b06-145 ◽

2006 ◽

Vol 84 (12) ◽

pp. 1908-1916

Author(s):

Natsuko I. Kobayashi ◽

Keitaro Tanoi ◽

Tomoko M. Nakanishi

Keyword(s):

Day Treatment ◽

Continuous Light ◽

Flower Induction ◽

Pharbitis Nil ◽

Elemental Distribution ◽

Short Day ◽

Induction Process ◽

Staining Methods ◽

First Time ◽

Flowering Process

We present the potential involvement of Mg2+ in the flowering mechanism in the shoot apex of the short-day plant Pharbitis nil (L.). To analyze elemental distribution in shoot apical meristems, fluorescence staining methods with Mag-fluo-4 AM and Fluo-3 AM were used. The former is sensitive to both Mg2+ and Ca2+, and the latter is a specific Ca2+ indicator. When plants were grown under continuous light conditions, some cells with intensive fluorescence of Mg2+ appeared in the top layers of the shoot apical meristem. During growth in the vegetative phase, cells in the center of the top layers accumulated large amounts of Mg2+. Exposure to a single 16 h short-day treatment induced the flowering process and dramatically reduced the fluorescence associated with Mg2+ accumulation in the top layers, suggesting that Mg2+ contributes to the flower induction process. The fluorescence associated with Ca2+ did not show this distribution difference between growth phases. A night-break treatment also influenced the fluorescence pattern. It was suggested for the first time that Mg2+ plays an important role in flower induction.

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Reduction in the critical dark length for flower induction during aging in the short-day plant Pharbitis nil var. Kidachi

Sexual Plant Reproduction ◽

10.1007/s00497-010-0139-7 ◽

2010 ◽

Vol 23 (4) ◽

pp. 291-300 ◽

Cited By ~ 1

Author(s):

Hiroshi Hasegawa ◽

Mizuki Yamada ◽

Yuiko Iwase ◽

Kaede C. Wada ◽

Kiyotoshi Takeno

Keyword(s):

Flower Induction ◽

Pharbitis Nil ◽

Short Day

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Echinacea purpurea `Magnus': Is It an Intermediate-day or a Short-day/Long-day Plant?

HortScience ◽

10.21273/hortsci.40.4.1100d ◽

2005 ◽

Vol 40 (4) ◽

pp. 1100D-1100

Author(s):

Ki Sun Kim ◽

Art Cameron ◽

Erik S. Runkle

Keyword(s):

Developmental Stage ◽

Continuous Light ◽

Echinacea Purpurea ◽

Flower Induction ◽

Research Groups ◽

Short Day ◽

Purple Coneflower ◽

Long Day ◽

Primary Induction ◽

Short Days

Echinacea purpurea Moench., or purple coneflower, has been classified both as an intermediate-day plant and a short-day/long-day plant by different research groups. We performed experiments to determine at what developmental stage Echinacea`Magnus' became sensitive to inductive photoperiods, and identified photoperiods that induced the most rapid flowering. Seedlings were raised under continuous light in 128-cell plug trays, then were transplanted into 11.4-cm plastic pots. Plants were transferred to 10-hour short days (sd) once seedlings developed 3, 4, 5, 6, 7, or 8 true leaves. After 4 or 6 weeks of sd treatment (primary induction), plants were moved to 16- or 24-hour photoperiods until flowering (secondary induction). Plants were also grown under continuous 10-, 14-, and 24-hour photoperiods to serve as controls. At least 4 leaves were required for flower induction; flowering was delayed and the percentage was low when plants had 3 leaves at the beginning of primary induction. Plants under continuous 14-hour photoperiods had the highest flower percentage (100%) and flowered earliest (87 days). Plants under continuous 10- and 24-hour photoperiods did not flower. Four weeks of sd followed by 16-hour photoperiods induced complete flowering and in an average of 95 days. However, 6 weeks sd was required for 100% flowering when the final photoperiod was 24 hours.

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The effect of photoperiodic treatments on mitotic activity in Pharbitic nil Chois

Acta Societatis Botanicorum Poloniae ◽

10.5586/1201 ◽

2014 ◽

Vol 60 (1-2) ◽

pp. 133-138

Author(s):

Joanna Czaplewska ◽

Jan Kopcewicz

Keyword(s):

Mitotic Activity ◽

Mitotic Index ◽

Dark Period ◽

Continuous Light ◽

The State ◽

Pharbitis Nil ◽

Shoot Apices ◽

Inductive Cycle ◽

Short Day ◽

Inductive Photoperiod

The short-day plant, Pharbitis nil, requires only a single inductive cycle with a 16-hour dark period for flowering. The mitotic activity in the shoot apices was studied directly after the termination of the inductive photoperiod. A pronounced rise in the mitotic index was found in the 2nd and the 8th-14th hours. Control plants grown under noninductive conditions (continuous light, a light interruption in the middle of the dark period) did not flower and did not show an increased mitotic index. The increased mitotic activity in the shoot apices of Pharbitis seems to be causally connected with the phytochrome-controlled entry of the plants into the state of generative induction.

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Semidian rhythmicity in the flowering response of Pharbitis nil to changes in temperature

Functional Plant Biology ◽

10.1071/pp97117 ◽

1998 ◽

Vol 25 (2) ◽

pp. 183 ◽

Cited By ~ 1

Author(s):

O.M. Heide ◽

R.W. King ◽

L.T Evans

Keyword(s):

Circadian Rhythm ◽

Constant Temperature ◽

Opposite Effect ◽

Dark Period ◽

Floral Induction ◽

Continuous Light ◽

The Other ◽

Pharbitis Nil ◽

Flowering Response ◽

Short Day

Our earlier experiments on flowering in the short day plant Pharbitis nil involved far- red/dark (FR/D) interruptions of 90 min duration at various times during a continuous light, constant temperature period before a single inductive dark period. They revealed a rhythm with a period of 12 h, hence semidian. We concluded that the phasing of this semidian rhythm determined the length of darkness required for floral induction. This conclusion has since been challenged so we sought other pretreatments which reveal the semidian rhythm. Interruptions at 12°C–17°C for 45–90 min at various times prior to the inductive dark period were as effective as FR/D in eliciting the semidian rhythm, with significant effects on flowering persisting for at least three cycles in constant conditions in continuous light. The rhythmic response to 12°C pretreatments was 3 h out of phase with that to FR/D pretreatments. Flowering responses to the semidian rhythm exposed by 12°C pretreatments were additive to and independent of those to a circadian rhythm. Some evidence was obtained of reversal of the inhibition or promotion of flowering by FR/D or 12°C by exposure immediately afterwards to the other pretreatment at times of their opposite effect. Pretreatments at 12°C, like those with FR/D, either reduced (if promotive) or extended (if inhibitory) the length of the dark period required for floral induction in this short day plant.

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The level of phyA in Pharbitis nil Chois during the photoperiodic flower induction

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.2000.035 ◽

2014 ◽

Vol 69 (4) ◽

pp. 269-272 ◽

Cited By ~ 1

Author(s):

Adriana Szmidt-Jaworska ◽

Krzysztof Jaworski ◽

Jan Kopcewicz

Keyword(s):

Dark Period ◽

Polyclonal Antibodies ◽

Flower Induction ◽

Pharbitis Nil ◽

Light Illumination ◽

Direct Control ◽

Short Day ◽

Rapid Destruction ◽

Photoperiodic Flower Induction

The aim of this work was to determine if there is any relationship between an endogenous phyA level and photoperiodic flower induction. The level of phyA was characterised with polyclonal antibodies directed to phyA from pea. At first it was detected that phyA level is predominant in cotyledons, whereas in roots and stems the concentration of labile phytochrome is rather low. So cotyledons were used for later experiments. In these cotyledons exposed to light illumination a rapid destruction of phyA has been observed. The loss of extractable phyA chromoprotein occurs already after 60 min of irradiation. Pharbitis nil is a short-day plant and a single 16-hours-long dark period is fully inductive. We assessed that phyA level is extremely low during a long inductive night and an immunodetectable phytochrome appears only after 24 hours of darkness. The obtained results suggest that labile phytochrome is not taking part in the direct control of the photoperiodic flower induction.

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Endogenous α-Ketol Linolenic Acid Levels in Short Day-Induced Cotyledons are Closely Related to Flower Induction in Pharbitis nil

Plant and Cell Physiology ◽

10.1093/pcp/pcg007 ◽

2003 ◽

Vol 44 (1) ◽

pp. 35-43 ◽

Cited By ~ 35

Author(s):

Masayuki Suzuki ◽

Shoko Yamaguchi ◽

Toshii Iida ◽

Ikue Hashimoto ◽

Hiromi Teranishi ◽

...

Keyword(s):

Linolenic Acid ◽

Flower Induction ◽

Pharbitis Nil ◽

Short Day

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Floral initiation under continuous light in Pharbitis nil, a typical short-day plant

Plant and Cell Physiology ◽

10.1093/oxfordjournals.pcp.a075015 ◽

1974 ◽

Keyword(s):

Continuous Light ◽

Pharbitis Nil ◽

Floral Initiation ◽

Short Day

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Influence of Daylength Delivery on Flowering in Several Herbaceous Perennial Species

HortScience ◽

10.21273/hortsci.30.4.861f ◽

1995 ◽

Vol 30 (4) ◽

pp. 861F-861

Author(s):

Cheryl Hamaker ◽

William H. Carlson ◽

Royal D. Heins ◽

Arthur C. Cameron

Keyword(s):

Continuous Light ◽

Flower Induction ◽

Perennial Species ◽

Herbaceous Perennials ◽

Short Day ◽

Long Day ◽

Herbaceous Perennial ◽

Campanula Carpatica

To determine the most effective lighting strategies for flower induction of long-day (LD) plants, 10 species of herbaceous perennials were chilled at 5C for 0 or 12 weeks and then forced at 20C under the following photoperiods: short day, 4-h night interruption (4-h NI), 7-h night interruption (7-h NI), 7-h day extension, 7-h predawn (7-h PD), and 24-h continuous light (24-h). All treatments consisted of a 9-h photoperiod of sunlight supplemented with 90 μmol·m–2 from HPS lamps. LD treatments were delivered by incandescent lights and induced flowering in obligate LD plants. Rate of flowering, height, and bud number at first flower varied among species and LD treatments. Although flowering was accelerated under 24-h and 7-h NI for most species, it was delayed under 24 h for Coreopsis verticillata `Moonbeam' and Campanula carpatica. For unchilled plants of most species, flowering was delayed under 7-h PD compared to other LD treatments. Chilling decreased time to flower and reduced differences between LD treatments. Coreopsis `Moonbeam' and C. Ianceolata `Early Sunrise' were shorter when grown under 4-h NI.

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